Investigating genome wide patterns of natural selection in eukaryotes

摘要: Mutations are the ultimate source of new genetic information and they can be neutral, harmful or beneficial. The fate all mutations is either to lost eventually become fixed in a population. In this thesis I investigate genome wide traces natural selection eukaryotes. focus on most common type mutations, point mutations, in protein coding genes. I investigated whether there adaptive evolution 11 plant species comparisons by applying an extension McDonald Kreitman (MK) test found little evidence of evolution. However, have low effective population sizes (Ne) rate thought correlated to Ne. therefore extended my study using additional data from mammals, drosophilids and yeast relationship between Ne. I highly significant correlation relative to the neutral (!a) Ne. It has been proposed that evidence artifact fluctuating selection. simulated model fluctuating selection, which average strength of selection acting upon zero. Under inferred using MK-type tests. become positively selected. signal genuine. Ne not only vary but also across genomes. how much variation is, affects efficiency natural unknown. I analysed 10 show variation Ne widespread. variation is limited, amounting few fold genomic regions. This is never-the-less sufficient cause selection.